Rocket motors having angularly movable exhaust nozzles

ABSTRACT

An angularly movable exhaust nozzle for a rocket motor having two concentric pairs of spherical mating surfaces provided between a forward portion attached to the motor and the exhaust nozzle, the proximity of the surfaces being such that an annular labyrinth passage is provided between them. There may be sealing means in the passage remote from the inner surface of the nozzle or a shroud surrounding the nozzle and ducting rearward gases escaping from the passage. The exhaust nozzle may be pivoted to the forward portion by means of a gimbal ring assembly.

United States Patent [191 Bligh et al.

[111 3,759,446 [451 Sept. 18,1973

[ ROCKET MOTORS HAVING ANGULARLY MOVABLE EXHAUST NOZZLES [75 Inventors:Jack 'B|'igh,"A" iebi1r/j Boeing hamshire; Kenneth Edward Silman,Wendover, Buckinghamshire, both of England [73 Assignee: The Secretaryof State for Defence in Her Britannic Majestys Government of the UnitedKingdom of Great Britain and Northern Ireland, London, England [22]Filed: Jan. 21, 1972 [21] Appl. No.: 219,772

[30] Foreign Application Priority Data Jan. 21, 1971 Great Britain2,845/71 [52] US. Cl. 239/265.35, 60/232 [51] Int. Cl B64d'33/04 [58]Field of Search 239/265.1l, 265.19,

[56] References Cited UNITED STATES PATENTS 3,048,977 8/1962 Geary, Jr.239/265.35

3,446,437 5/1969 McCullough et al. 239/265.35 3,090,198 5/1963 Zeisloft239/265.35 3,056,577 10/1962 Kulisek 239/DIG. 19 3,208,215 9/1965 Brown239/265.35 3,049,877 8/1962 Sherman 239/265.35 X 3,401,887 9/1968Sheppard 239/265.35 3,451,625 6/1969 Fruktaw 239/265.35 3,659,788 5/1972Oldfield et al... 239/265.35 X 3,270,505 9/1966 Crabill et al.239/265.35

Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Michael MarAttorney-Harry Saragovitz et al.

[57] ABSTRACT An angularly movable exhaust nozzle for a rocket motorhaving two concentric pairs of spherical mating surfaces providedbetween a forward portion attached to the motor and the exhaust nozzle,the proximity of the surfaces being such that an annular labyrinthpassage is provided between them. There may be sealing means in thepassage remote from the inner surface of the nozzle or a shroudsurrounding the nozzle and'ducting rearward gases escaping from thepassage.

The exhaust nozzle may be pivoted to the forward portion by means of agimbal ring assembly.

8 Claims, 3 D1 56]; age

PATENIEDSEPIBW 3.159.446

SHEEI 2 BF 2 FIG. 2

FIG. 3

ROCKET MOTORS HAVING ANGULARLY MOVABLE EXHAUST NOZZLES This inventionrelates to exhaust nozzle assemblies for rocket motors having angularlymovable exhaust nozzles.

Rocket motors are provided with angularly movable exhaustnozzles wherebyangular adjustment of the nozzle with respect to the motor changes thethrust vector of the exhaust gases leaving the nozzle and hence providesa means of changing the line of flight of the rocket motor.

Difficulties have been experienced with known rocket motors havingangularly movable exhaust nozzles due to the problem of having toprovide an efficient gas seal at the nozzle throat and also because ithas been found that high torque loads are required to actuate the nozzlewhich leads to a weight and power penalty.

It is an object of the present invention to provide an improved exhaustnozzle assembly for a rocket motor having an angularly movable exhaustnozzle.

An exhaust nozzle assembly for a rocket motor according to the presentinvention has a forward portion for attachment to the motor and anexhaust nozzle providing a passage for exhaust gases from the motor, support means for supporting the exhaust nozzle on the forward portion forangular movement with respect to the motor, a first part sphericalmember on the nozzle for sliding engagement with a first correspondingcomplementary part spherical member on the forward portion, secondmembers on-the nozzle and the forward portion respectively which definea nozzle throat at their inner surface and have corresponding partspherical complementary surfaces for sliding engagement with each other,there being defined between the complementary first members, between thefirst members and the second members, and, between the second members anannular labyrinth passage.

In one embodiment annular sealing means are provided in the labyrinthpassage between'said first members and remote from the inner surface ofthe nozzle throat.

In a further embodiment a flexible gas tight annular I fore and aft axisof. the motor may be provided by a gimbal ring support arrangement inwhich a gimbal ring is supported for angular movement about one saypitch.

axis on trunnions pivotally supported on the motor and which ring inturn supports the nozzle for angular movement on trunnions about asecond, yaw axis normal to the pitch axis.

Three embodiments of the invention are illustrated by way of example inthe accompanying diagrammatic drawings of which:

FIG. 1 is a half sectional side elevation of a first embodiment andFIGS. 2 and 3 are sectional half view side elevations of a second andthirdembodiment, respectively.

Referring first to FIG. 1 the rear end region of a rocket motor is shownat 11 and an exhaust nozzle at 12. Two support arms 13 extend from theend region 11 and carry trunnions 14 which support a gimbal ring 15 forangular motion about a yaw axis Y--Y which is normal to the fore and aftaxis of the rocket motor. The nozzle 12 comprises a rear part 16 athroat part 17 and a male seal housing 18. Two support arms, one ofwhich is shown at 19 extend forwardly from the throat part 17 and aresupported by trunnions, one of which is shown at 20, on the gimbal ring15 for angular movement about a pitch axis P which is normal to the yawaxis Y-Y.

A venturi throat is defined by the inner surfaces 21, 22 of the rearpart 16 and throat 17, and, the inner surface 23 of the rear region 11of the rocket motor. A part spherical concave surface 24 to the rear ofthe surface 23 complements a corresponding part spherical convex surface25. An annular female seal housing 26 is secured to the end region 11and has a part spherical concave surface 27 which complements acorresponding part spherical convex surface 28 on the male seal housing18.

A polytetrafluoroethylene lip seal 29 is housed in a channel 30 in inthe housing 26 and sealed against the surface 28.

A layer of insulating material 31 is secured to the housing 18.

- An annular labyrinth type channel is thus formed between. the surfaces24, 25 and the items l7, ll, 26, 31 and 18 extending as far as the lipseal 29.

Power actuators (not shown) are provided for moving the nozzle angularlyon the gimbal support with respect to the rocket motor.

In practiceit is found that because of the gimbal suport the actuatorforces required are low. Also, the close fit between the surfaces 24, 25and 27, 28 and the extended nature of the labyrinth channel prevents ordelays erosion and leakage past the lip seal 29.

The embodiment shown at FIG. 2 is basically similar to that of FIG. 1except that the lip seal 29 is not used and a shroud 32 is provided toduct any leakinggases to the rear.

The embodiment of FIG. 3 is also basically similar to that of FIG. 1except that an annular flexible gaiter 34 of Hypalon (Registered TradeMark) or butyl rubber bridges the annular channel and the space 35formed between it and the lip seal is filled with a silicone oil orsimilar type of fluid which comprises both a heat sin for coolingand-also acts as a lubricant.

-As shown the concave surfaces 24, 27 are on the forward portion and theconvex surfaces are on the angularly movable nozzle but it will beapparent that the surfaces could be reversed'.

In the embodiments shown the nozzle has two degrees of freedom which areprovided by the gimbal'support. However, in some cases a single degreeof freedom will suffice. Thus, in the case of a motor having fourexhaust nozzles, one opposed pair of nozzles may be supported to have asingle degree of freedom about the same say pitch axis whilst the otheropposed pair are supported to have a single degree of freedom about thesame say yaw axis normal to said pitch axis. With this arrangementdifferential adjustment of the pairs will provide the necessary thrustvector control.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An exhaust nozzle assembly for a rocket motor, having a forwardportion for attachement to the motor, an exhaust nozzle providing apassage for exhaust gases from the motor, support means for supportingthe exhaust nozzle on the forward portion for angular movement withrespect to the motor, a first part spherical member on the nozzle forsliding engagement with a first corresponding complementary partspherical member on the forward portion, second members on the nozzleand the forward portion respectively which define a nozzle throat attheir inner surface and have corresponding part spherical complementarysurfaces for sliding engagement with each other, there being definedbetween the complementary first members, between the first members andthe second members, and, between the second members, an annularlabyrinth passage, and having a shroud surrounding the exhaust nozzle,for directing rearward gases leaking from the laybyrinth passage.

2. An exhaust nozzle as claimed in claim 1 and having annular sealingmeans located in thelabyrinth passage between said first members andremote from the inner surface of the nozzle throat.

3. An exhaust nozzle as claimed in claim 1 and having a flexible gastight annular gaiter bridging the labyrinth passage between the firstmembers and the second members.

4. An exhaust nozzle as claimed in claim 2 and having a flexible gastight annular gaiter bridging the labyrinth passage between the firstmembers and the second members, and wherein the space between the gaiterand the annular sealing means is filled with a liquid.

5. An exhaust nozzle as claimed in claim 4 and wherein the liquid is asilicone oil.

6. An exhaust nozzle as claimed in claim 1 wherein part of the labyrinthpassage is lined with an insulating material.

7. An exhaust nozzle as claimed in claim 2, and wherein the sealingmeans are made of polytetraflurorethylene.

8. An exhaust nozzle as claimed in'claim l and having a gimbal ring, afirst trunnion on said ring for pivotal mounting on the motor, and asecond trunnion on said ring and supporting said nozzle.

1. An exhaust nozzle assembly for a rocket motor, having a forwardportion for attachement to the motor, an exhaust nozzle providing apassage for exhaust gases frOm the motor, support means for supportingthe exhaust nozzle on the forward portion for angular movement withrespect to the motor, a first part spherical member on the nozzle forsliding engagement with a first corresponding complementary partspherical member on the forward portion, second members on the nozzleand the forward portion respectively which define a nozzle throat attheir inner surface and have corresponding part spherical complementarysurfaces for sliding engagement with each other, there being definedbetween the complementary first members, between the first members andthe second members, and, between the second members, an annularlabyrinth passage, and having a shroud surrounding the exhaust nozzle,for directing rearward gases leaking from the laybyrinth passage.
 2. Anexhaust nozzle as claimed in claim 1 and having annular sealing meanslocated in the labyrinth passage between said first members and remotefrom the inner surface of the nozzle throat.
 3. An exhaust nozzle asclaimed in claim 1 and having a flexible gas tight annular gaiterbridging the labyrinth passage between the first members and the secondmembers.
 4. An exhaust nozzle as claimed in claim 2 and having aflexible gas tight annular gaiter bridging the labyrinth passage betweenthe first members and the second members, and wherein the space betweenthe gaiter and the annular sealing means is filled with a liquid.
 5. Anexhaust nozzle as claimed in claim 4 and wherein the liquid is asilicone oil.
 6. An exhaust nozzle as claimed in claim 1 wherein part ofthe labyrinth passage is lined with an insulating material.
 7. Anexhaust nozzle as claimed in claim 2, and wherein the sealing means aremade of polytetraflurorethylene.
 8. An exhaust nozzle as claimed inclaim 1 and having a gimbal ring, a first trunnion on said ring forpivotal mounting on the motor, and a second trunnion on said ring andsupporting said nozzle.